[Yajie_Qin]

Now I am simulating an axial Fan in wind tunnel refer to the ISO5801 type C. In order to get the fan P-Q curve, the inlet total pressure (a point on the axis 1m upstream the inlet plane Pt) is monitored. My question is that the Pt does not converging after few hundreds steps. The test valve is 252Pa, the simulated Pt jump around 250 Pa and has an amplitude about 30Pa.
I do the simulation with FLUENT 3d steady simulation. The simulation domain consists of three zones one inlet chamber zone, one rotating fan zone(MRF method 1486rpm) and one ambient outlet zone.
Other simulation as flowing:

• energy: off
• turbulent model:sst-kw
• density method: constant 1.2 kg/m3
• inlet: massflow inlet, 0.24kg/s
• outlet:pressure outlet, 0Pa
• pressure-velocity :Coupled
• spatial discretization : pressure, momentum, k and w are all second order upwind
• Pseudo time method: global time step (time scale factor 2)

Can any one explain why? Thank you in ahead!!